The character 奋 (fèn) conveys the meaning of exerting effort, striving, or being vigorous. It often appears in compound words like 奋战 (to fight bravely) and 奋斗 (to struggle/strive). In the expression 死奋战, it emphasizes fighting with every ounce of energy.
他奋力地向前跑,终于追上了那辆公交车。
Tā fènlì de xiàng qián pǎo, zhōngyú zhuī shàngle nà liàng gōngjiāo chē.
He ran forward with all his might and finally caught up with that bus.
战士们奋战到最后一刻,绝不投降。
Zhànshìmen fènzhàn dào zuìhòu yīkè, jué bù tóuxiáng.
The warriors fought to the very last moment and would never surrender.
她一直在为自己的梦想奋斗,从来不停下脚步。
Tā yīzhí zài wèi zìjǐ de mèngxiǎng fèndòu, cónglái bù tíng xià jiǎobù.
She has always been striving for her dream, never stopping for a moment.